Investigating Mutations with Legos
Names:____________________________________
__________________________________________
Introduction: We have been learning about DNA and protein synthesis. We know that the genes on DNA
carry the genetic code for amino acid sequences that determine protein structure and function. In the
processes of transcription and translation, two types of RNA – mRNA & tRNA- are necessary for copying
the code of DNA to take out of the nucleus and translating nucleotide code to amino acid order. In this
investigation, we are going to investigate the affect of various types of mutations on protein structure.
In order to do this, please define the terms below:
Point Mutation
Substition Mutation
Deletion Mutation
Insertion Mutation
Nonsense Mutation
Missense Mutation
Silent Mutation
Purpose: You will work in groups of three to compare three different Lego block proteins. Each person will
be attempting to build the SAME protein but only one will have the normal mRNA nucleotide sequence.
The other two group members will have mutations affecting the mRNA sequence, and therefore the protein.
After building, compare the three proteins to see how the mutations have changed the structure.
PART 1
Procedure:
1. Decide who will build proteins A, B, and C.
2. Write the mRNA codons and tRNA anticodons in the chart below your assigned DNA sequence.
2. Write the corresponding block color in the data table.
3. Build your Lego Protein.
4. Compare your tower to your lab partners. Remember that all three sequences are supposed to yield the same protein.
A. DNA sequence from the normal gene: 3’AAATTTCCCGGGGGACGACCAGGACTCCTC5’
mRNA codon
Anticodon on the tRNA
Lego Block Color
Position in protein
Top
2
3
4
5
6
7
8
9
Bottom
B. DNA sequence resulting from mutation 1: 3’AAATTTCCTGGGGGACGACCAGGACTCCTC5’
mRNA codon
Anticodon on the tRNA
Lego Block Color
Position in protein
Top
2
3
4
5
6
7
8
9
Bottom
C. DNA sequence resulting from mutation 2: 3’AAATTTCCCGGGGGATCGACCAGGACTCCT5’
mRNA codon
Anticodon on the tRNA
Lego Block Color
Position in protein
Top
2
3
4
5
6
7
8
9
Bottom
Part 1 Questions
1. Compare all three amino acid sequences. How does the amino acid sequence differ between the
normal sequence and the sequence with Mutation 1?
2. Circle the difference between sequence A and B.
3. How does the amino acid sequence differ between the normal sequence and the sequence with
Mutation 2?
4. Circle the difference between DNA sequences A and C.
5. What type of mutation is mutation 1?(More than one term may describe this.)
6. What type of mutation is mutation 2?(More than one term may describe this.)
7. Of the two mutations, which type of mutation has a greater affect on the final amino acid sequence?
Why?
PART 2
Now take apart your Lego towers. You will follow the same procedurę as in Part 1, but with new DNA
sequences.
This time, you need to decide who is building protein D, E, or F
D. DNA sequence for the normal gene: 3’ACCTGAAAATGGTTCCTCCCATCCCGTCCC5’
mRNA codon
Anticodon on the tRNA
Lego Block Color
Position in protein
Top
2
3
4
5
6
7
8
9
Bottom
E. DNA sequence for mutation 3: 3’ACCTGAAAATGGTTGCTCCCATCCCGTCCC5’
mRNA codon
Anticodon on the tRNA
Lego Block Color
Position in protein
Top
2
3
4
5
6
7
8
9
Bottom
F. DNA sequence for mutation 4 3’ACCTGAAAATGGGTCCTCCCATCCCGTCCC5’
mRNA codon
Anticodon on the tRNA
Lego Block Color
Position in protein
Top
2
3
4
5
6
7
8
9
Bottom
Part 2 Questions
1. How does the amino acid sequence differ between the normal sequence and the sequence with
Mutation 3?
2. Circle the difference between sequence D and E.
3. How does the amino acid sequence differ between the normal sequence and the sequence with
Mutation 4?
4. Circle the difference between DNA sequences D and F.
5. What type of mutation is mutation 3?(More than one term may describe this.)
6. What type of mutation is mutation 4?(More than one term may describe this.)
7. Of the two mutations, which type of mutation has a greater affect on the final amino acid sequence?
Why?
8. How are missense and nonsense mutations different?
9. What conclusions can you draw about substitution mutations?
10. Evaluate the following statement: „Mutations are always bad for an organism.”
11. When do these DNA mutations occur?
12. It is estimated that every human carries 9 lethal mutations that they inherited from one of their
parents. This means that there are 9 genes for essential proteins that are mutated in such a way that
either no protein is made or a non functioning protein is made. If this is true, why do we not suffer
from these disorders?
Codon Color Chart
U
C
A
G
U
C
A
G
green
blue
green
yellow
brown
blue
yellow
blue
blue
red
red
yellow
Black/pink
green
brown
pink
yellow
black/pink
green
red
red
black/pink
red
blue
red
blue
blue
pink
brown
blue
red
green
green
black/pink
brown
pink
brown
green
black/pink
stop
yellow
brown
white
brown
red
blue
pink
yellow
red
red
blue
yellow
blue
green
brown
stop
Black/pink
green
green
white
orange
brown
blue
black/pink
Each bag should contain:
Green-4
Red-5
White-3
Black or Pink-6
Yellow-5
Blue-3
Orange-2
Brown-2
U
C
A
G
U
C
A
G
U
C
A
G
U
C
A
G